Multiphase induction-furnace.



J. R. WYATT.

I MULTIPHASE mnucnou FURNACE.

APPLICATIONFILED JULY 19. I916- 1, 235,630. Patented Aug. 7, 1917.

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J. R. WYATT.

MULTIPHASE INDUCTION FURNACE. APPLICATION FILED JULY 19' I916.

Patented Aug. 7, 191 7.

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1:" i 37 i 4 l I I v 35 33 FIGJEL attain-21g JAMES B. WYATT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGN'OB T AJAX METAL COMPANY, INCORPORATED, 0F PHILADELPHIA, PENNSYLVANIA, A GOR- PORATION 01: IA.

To all whom it may concern:

Be it known tht I, JArms R. write, 'a

citizen of 'the United States, residing at.

2024' S. 21st street, Philadelphia, in the .5 county of Philadelphia and State of Penn-- have invented a-certai'n new andsylyania, 1 useful Multiphase Induction-Furnace, which the following is a specification.

The purpose of my invention is to intermingle to the best advantage the stirring eifects from several heating channels in an induction furnace.

A further purpose of my invention is to distribute a plurality of heating channelsin new cooperative relation to a furnace pool. j A further purpose of my invention is to combine a plurality of acute-angled heating channels inthe m xing and heating of a furnace .pool by combinations of motor effects, preferably using multi phase current for this purpose, one phase for each channel. This secures uniformity in the molten fluxes combined, at the same time that the several phasesof current are steadied and unbalancing avoided.

Further purposes of my invention will appear in the specification and claims hereof.

I have preferred to illustrate my invention by a few only of the variousforms in which it may be applied, selecting forms varying in phase, number of channels and location of the channels-to illustrate types of variations among many which may exist. Figure 1 is a top plan view of a furnace embodying the preferred form of my invention. V

Fig. 2 is a horizontal section of Fig. 1 taken through the three channels just above the transformer core. The electrical connections are shown diagrammatically.-

Fig. 3 is a top plan view, also with diagrammatic electrical connections, showing a second form of my invention. Figs. 4 and 5 are an end elevation and side elevation respectively of another construction. 5

Fig. 6 is a side of my invention.-

Figs. 7 8 and partly broken away, in which two channels ranged may be located.

elevation of a third form 9 are top plan views, showing various ways horizontally armnucrrou-rpnuacn.

' Specification of Letters Patent.

v Patented'A'ug. 7; 1917. Application filed J'ulylS, 1 91s." seri l ze/noses Similar numeralsof reference indicate like parts. 1 v

. This application is va division in part, plus additional matter of an application filed by :me January 24, 1916, Serial No,

73,810 for induction furnace.

In all of the forms of my invention illustrated, I have intended to show the channels so arranged as to produce high motor effect by forming the bend in each channel outside of the pool at'an acute angle with obtuse angled connections between. the ends of the channel and the pool and have planned to use a channel having relatively great width parallel to the included transformer leg, as

compared with the thickness-of the channel,

perpendicularly thereto, making it possible for me to obtain a high power factor for the circuits at the sametime that thejmotor effect in the acute angle is made a maximum. I recognize that the-width dare not be so' small as to giv excemive'fiuid and fric- 14, meeting in acute angles 15, 15', 15 and having their cross sections in proximity.

much wider than they are thick. The Walls 16 are made of any suitable refractory, or casing lined with refractory-material.

all of the illustrations I prefer to use metal pool jackets and metalcasings for the channels, lined by a cementitious asbestos refractory rammed to place about a mold defining the channel and pool and subseor otherwise removing the pattern. c

vThe center lines of the two branches of each channel lie in a vertical plane, the planes being here shown as making angles of 60 with each other. 7

Where the channel branches 13, 14:, 13', 14'', 13 14 connect withthe bottom of the pool, as at 17, 18, 17, 18', 17 18 ,-the near -qu,ently carefully dried out after burning and 2 the transformer 20 is of speed of the downward edges or" the connections are chamfered, rounded, or the channel curved, as at 19, so that the effective electric connectionthrough the channel and pool across the pool follows an obtuse-angled path at each channel connection with the pool avoiding here the motor-effect sought at the corners 15, 15, 15 as motor efl'ect originating at the pool ends of the channel forms a disturbing element opposing the flow produced by the motor effect at the corners 15, 15, 15

In each of the channels in this and in the other illustrations, the molten channel content is a conductor in which, as a secondary, current is induced by a transformer which embraces one 01": the branches. In Figs. 1 ring type having star legs 21 upon each of which a coil 22 is located, the three-phase current connections being shown in star form also.

The induced flow of the electricity in the channels as secondaries has diverse direction upon opposite sides of the bends at 15, 15, 15 resulting in a highly developed motor efi'ect which is greatest at the corner and diminishes gradually toward the points of connection with the pool and which, there fore, having the portion in the rear always driving that nearer the furnace upon the outside part of the channel prevents interruption of the upwardly flowing heated channel metal by the stream of downwardly flowing cooler metal which takes its place. The flow of cooler metal depends in part upon the height of the hydraulic. head exerting pressure upon it.

The outward flow of hotter metal from the channel ends into the pool is indicated by the heads of the arrows and the inward flow of cooler metal is indicated by the tails of the arrows. From this it will be evident that the triangular arrangement'of the channels with adjacent terminals results in equidistant combined bands or whirls of flow from as near the edge of the pool as may be selected for the channel terminals toward the center and into the channels again. The efl'ect might be compared with rolling rings each part moving in the plane of its radius and the axisi of the rings.

(Ill operation I find itquite desirable to pour .the initial charge from-another furnace. The current is then turned on and heating of that charge and material added from time to time is eflected by the'secondary current. The combined motor eflects quickly and thoroughly mix the hotter metal within the channel with thatin the pool.

It will be evident that-the extent of combination of flows due to' adjoining channel outlets will depend in large measure upon,

the sizes of the channels, the nearness to each other of their adjoining outlets and the outlets of different close to each other.

channels are closed, as

might be termed whirl sheets extending a considerable part of the distance from one end of the pool to the other.

In the form shown in Figs. 4 and 5 the construction is intended to be'substantially the same as in Fig. 3, except that the axis of the cylindrical furnace body 11' forming the pool is horizontaland the channels depend from the side of the cylinder. The electrical connections may be of the star-type, as in Fig. 2, or of the delta-type, as seen in Fig. 3. Here the operation of the several channels upon the pool will be aifected, if the channel terminals be near the edge of the pool, by the fact that the-discharge from the channels will be nearly tangent to the inner walls of the pool.

of the outlets to the inner walls to be substantially In each of Figs. 3, 4: and 5 the channel.

a planes are vertical, and the combined eitect will be increased by bringing the adjoining channels into the pool It will also be afiected by the size of the pool.

In all of these figures I have located truntionally, without considering it necessary to show mechanism by which the actual turn- 4 and 5 to interrupt the channels at some such points, as at 26, by joints which disturb the electrical conductivity of the channel casing for travel of secondary current and give opportunity for insertion of a transformer Without separation of the transformer parts.

acter of the joint will depend upon the shape,

nions 23 and pouring spouts 24 conven- The exact location and char material and electrical, as well as mechanical design and must, with this suggestion, be left to the judgment of the engineer.

In the form shown in Figs. 6 and 7 the in the previous fig- .here connected with the pool jacket by any suitable flanges and retainers, at 27 As the height of head of the. poolv above the channel maylvary between any limits set by the designer, so may it also be" omitted and the channels be open and at the level of 0, the pool, as in Fig. 8. Other differences between the Figs. 7 and 8 lie in the fact that Fig.7 uses a metallic-casing for the channel apd jacket for the pool, whereas Fig. 8

uses a refractory material of uniform com:

5 position'for the entire crucible, requiring that one of the transformer legs'2l be separable so that item be placed about the channel.

' Another difference between the forins of Figs. 7 and 8 is that the adjoining channel sides areunited in a, common channel 28 in Fig. 7, whereas, the channels are distinct in Fig. 8. Uniting the channels into one short-er channel has some advantage in twophase work, because of the differing electrical requirements of the 'common path, con .veniently met here by the construction which shortens the channel 28, as compared with channels 17 and 18 as l to 1.4. Be

cause of the Opp sing forces from the twoangles having their inner points at 29 and 80, the flow of metal within channel 28 would not be as sharply and clearly defined as within the channels 17 and 18. x

Except for the difference in height of the pool, the'position of the spout and the division of the'casing in one and absence of division line in the crucible of the other, Fig. 6 would serve as side elevation of either of Figs. 7 and 8m -The spout has'been shown at the left in Figs. 6 and 7 on the same sidev as the channel, a form which offers advantages in permitting the secondary circuit to be maintained during pouring of the heats though it may require that the molds be placed after tilting has begun.

The trunnion 23 have been shown at the sides of the furnace bodies in all the figures except Fig. 9, where they are located inline with the ends of the channels; but differing purposes and. pouring arrangement would cause yarigion 'in the I application of my invention in is .as in other particulars.

In Fig. 9 the location of the channels at opposite ends results in the metal coming V out from the channels in directions almostdirectly opposite at the two sides of the pool.

, If the distance between benot too great, so these two fluxes of molten metal will tend to scour the outerf(coo1er) part of the pool, turning the metal there toward thecenter, and the two streams will mutually divert each other. The action may be varied 'in the content of each 0 by the contour given the inner surface of the pool between these twopoints. It will be obvious that the combination of two series of loops of outwardly and inwardly flowing molten metal each loop reaching and leaving the pool at nearly the same points will cause a morepowerful, as well as difi'erent ultimate fiow that could be secured by the channels separately.

It will be evident that the number of channels used in Figs. 4 and 5 should most desirably agree with the number of phases of current used or the sum of the phases where difierent circuits are employed.

Having thus described my invention, what I claim as new and desire to secure by .Letters Patent is:

1. In an induction furnace, a furnace body adapted to contain a pool, in combination with walls forming a plurality of channels meeting the pool in a generally upward direction and multiphase transformer means for applying a different phase of the current to the induction of current as secondary in each of the'channels. l

2. In an induction furnace, a furnace body adapted to contain a pool, walls forming a plurality of channels beneath the pool in triangular arrangement and having the bends in the channels outside of the pool of acute angle form, in combination with transformer means for inducin flow of electricity the channels as a secondary.

- 3. Inan induction furnace, a furnace body adapted to contain a pool, walls forming three channels connecting therewith, contiguous connections of different channels being located near the apices of a nearly equilateral triangle, in combination with a threephase transformer embracing one leg of each channel, I v

4. In an induction furnace, a furnace body adapted to contain a pool, in combination with walls-forming a plurality of upwardly walls forming a plurality of acute-angled channels connected with the furnace body at both ends at substantially the'same height l well below the surface of the pool and a multi-phasetra'nsformer corresponding in phase t'othe number of channels and em-' forming two acute-angled channels'outside of the pool, having contiguous branchesof 'the two channels united in a common channel shorter than the more remote-channel branches, in combination withjtwo-phase,

transformer means for inducing current in the channels, as secondaries.

7. In an induction furnace, walls forming a-furnacebody adapted to contain a pool, in combination with walls forming channels on opposite ends of the pool, trunnions at .the ends, a spout located at the side of the pool between the channels and transformer mean -for induclng flow of current as secondarles 1n the two channels.

8. an induction furnace, walls forming a furnace body adapted to contain a pool,

Gopies of this patent may be obtained for in combination with walls forming channels at opposite sides of the pool, connecting with it at the channel ends and acute-angled outside of the furnace body, directing flow of hot metal from the outside of opposite channels toward each other near the outside of the pool, and transformer means five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

